Alright.. I believe I'm 98.999% sure I tracked down (and confirmed via purchasing) what indicator lamp lens that Dumble used for SSS #004. I am still unsure what bulb socket was used based on the very blurry gut shot, but I have a pretty good idea how it is visually put together. 
Blue Dialight/Dialamp 135 series lens caps. The data sheet says 9/16 27 threads for the cap BUT I found that standard Fender type T47 T3 1/4 bayonet style sockets are 9/16 24 and the Dialight 135 lens screws in securely without any indication that the threads are cross threading. 
https://www.mouser.com/datasheet/2/109/ ... 265505.pdf
135 – 32xx – 003
I picked up a NOS Dialight T3 1/4 socket (95 series) 
https://www.mouser.com/ds/2/109/07D-55744.pdf but there is an extra flange on the outside that doesn't quite look right when I compared to pictures of #004. I found 
https://www.amplifiedparts.com/products ... relampable and will be using this one instead of a standard Fender bulb holder. 
Some pictures of the combination of parts I picked up. 
Screen Shot 2018-09-20 at 6.27.23 PM.png
Screen Shot 2018-09-20 at 6.27.37 PM.png
Screen Shot 2018-09-20 at 6.27.50 PM.png
Screen Shot 2018-09-20 at 6.28.14 PM.png
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